The time-varying of the corrosion potential and corrosion current of coral aggregate concrete reinforcement at different voltage values was analyzed by linear polarization resistance and electrochemical impedance spectroscopy. The resistivity and porosity of coral aggregate concrete and ordinary concrete were tested. The critical chloride ion concentration of two kinds of concrete was studied. The results show that the stable period of corrosion potential and corrosion current of coral aggregate concrete is shorter than that of ordinary concrete under the same voltage. The critical chloride ion concentration of coral aggregate concrete is lower than that of ordinary concrete.